The present invention relates to the general art of securely anchoring loaded rope or cable hanging from upper stories of structures, and to the particular field of portable, quickly deployable support systems for raising and lowering loads in emergency situations.
The proliferation of high-rise office and residential buildings in areas of dense population is well-known. These buildings present various problems, among them raising and lowering heavy loads to upper stories, whether in emergency situations such as fire, or during construction or repair of a building. Another problem is the need for anchoring devices for fall prevention equipment during construction or repair. Such anchoring devices are subject to OSHA and ANSI requirements that they be deployed proximate to the point of use, i. e. the worksite, and that they pass a multi-directional pull test.
Many modern buildings do not have load-bearing walls, but rather are supported by a skeleton of steel, and the exterior walls are simply sheathing. In a construction situation, the use of a mobile crane that rises from the ground can be very expensive. Portable roof-mounted booms or derricks have been developed for lifting construction materials to the topmost level of a building under construction. U.S. Pat. No. 6,135,300 discloses a light-weight hoisting apparatus with a boom which can be mounted on a roof parapet wall within minutes. The parapet wall must be steel-reinforced concrete or construction of equivalent strength, thus the device is purposely designed so that it cannot be installed on 8 inch concrete block walls, which are typically not steel reinforced.
Such roof-mounted systems could undoubtedly lower loads as well as raise them, but they do not address emergency needs. Specifically they do not solve the problem of quick deployment of an anchoring system in an emergency situation at upper story balconies and windows lower than the roof, while providing removable attachment to the structure which is of sufficient strength to support the weight of heavy loads, together with reinforcing support of a ceiling in danger of collapsing, when the structure is on fire or otherwise damaged.
There are also numerous devices designed to lower persons from burning high-rise buildings. These inventions for the most part include various cable systems with braking systems for controlling the speed of descent. Only a few of these inventions address the problem of providing a framework for supporting the controlled descent devices, or fall prevention equipment, that is both portable and secure. One of these is an emergency cable descent system disclosed in U.S. Pat No. 5,343,981. This invention includes a boom which can be pivoted outside a window of a building to support a cable away from the exterior wall. This invention does not teach detachability of the boom, any device to limit rotation of the boom when a fixed position of it is desired, or a mode of attachment of the boom to the building which is strong enough to support a heavy load when the exterior wall is not a load-bearing wall. Neither does it appear that this system is adaptable to being deployed from a balcony. Further, it does not teach its application to the task of anchoring fall prevention equipment.
Another relevant invention is disclosed in U.S. Pat. No. 4,671,384. The controlled descent device and cable are suspended from a ladder-like frame which forms a U at its top which straddles a window ledge. There is no boom to hold the load away from the wall of the structure. This system does not appear to be deployable from a balcony that does not have a load-bearing railing, neither are strength of the attachment of the frame to the window ledge, nor detachability, addressed. This device obviously would not pass a multi-directional pull test because it could be dislodged by a pulling force from certain directions.
U. S. Pat. No. 4,503,933 teaches an emergency device stowed in a compact enclosure attached to the lintel of an upper-story window. This addresses the cosmetic problem of unsightliness presented by permanently mounted support frameworks. But this invention has no boom to hold the load away from the walls of the structure.
Accordingly there is a need to provide a multi-purpose portable anchoring device for lifting and lowering equipment for loads to be delivered to or lowered from an upper story of a building, which can be deployed easily and quickly, either on a balcony or in the interior of the building proximate to a window, which adapts to a structure not having load-bearing exterior walls or balcony rails, having a boom which keeps the load away from the exterior side of the building, which can support a winch or reel assembly for a cable, is adjustable to fit varying ceiling heights, and is removable when not in use, so that it does not detract from the appearance of the building. Preferably the device should be adapted to use as an anchoring device for fall-prevention equipment as well.
The present invention is a multi-purpose portable davit anchoring system comprising a sectional vertical support mast which comes apart for compact stowage and is easily reassembled. The support mast incorporates a screw jack assembly which adjusts the height of the mast and biases the support mast between two opposing surfaces, such as a floor and ceiling. The biasing action enables it to be firmly yet removably attached to a building wherein the exterior walls are not load-bearing but merely sheathing, and to provide support for a damaged ceiling that might otherwise collapse. A boom member is removably fastened to the support mast, for deploying a lifting and lowering cable away from the side of the building. A mounting plate is provided for a winch assembly that can wind up the cable or release it at a controlled rate of speed. Optional low profile upper and lower brackets for receiving the ends of the support mast may be permanently mounted at several locations on each floor of the building with minimal effect on the appearance of the building.
It is thus an object of this invention to provide a new multi-purpose portable davit anchoring system that is easily deployed within a few minutes, that is easily disassembled for stowage when not in use, and that incorporates certain useful features of the prior art, while overcoming some of the disadvantages thereof, which have not been anticipated, rendered obvious, suggested or implied by prior art systems.
It is a further object of this invention to provide a new multi-purpose portable davit anchoring system that provides means of strong attachment to a structure without requiring permanently attached mounting brackets or connections.
Another object of the invention is to provide a new multi-purpose portable davit anchoring system which can be firmly and removably attached to a building which has no load-bearing exterior walls.
It is a further object of this invention to provide a new multi-purpose portable davit anchoring system with a boom that can be temporarily locked in position so that it does not rotate or swing on its mounting pin to an unsafe position too close to the structure where it is deployed.
Still another object of this invention is to provide a multi-purpose portable anchoring system which can support any of a variety of controlled descent winches, (including motorized, remote controlled winches), rope and cable winding devices, rappelling equipment, and other rope- or cable-involved operations for use in emergency environments.
Yet another object of this invention is to provide a multi-purpose portable anchoring system that can be removably deployed from any floor of a high-rise building.
Yet another object of this invention is to provide a multi-purpose portable anchoring system that meets OSHA and ANSI requirements for devices designed to support fall-prevention equipment at high-rise construction sites.